Lighting device having backlighting, illumination and display applications

Abstract

The present invention provides a lighting device such as a backlighting device, and display thereof such as LCD display. The lighting device comprises one or more radiation sources such as UV-blue LED and a layer of air- and moisture-sensitive phosphor, such as complex fluoride activated with Mn 4+ . The phosphor layer is protected from air and moisture by placing it between two moisture/air impermeable members. The lighting device exhibits increased life, reliability and color stability over time and absence of restrictions imposed on the LED spacing, among others.

1 . A lighting device, which comprises one or more radiation sources and a layer of moisture sensitive phosphor, wherein said layer of phosphor is located between opposed at least substantially transparent members comprised of a material substantially impervious to an external atmosphere. 
     
     
         2 . The lighting device of  claim 1 , wherein the phosphor is selected from sulfides, selenides, tellurides, activated with at least one of Ce 3+  and Eu 2+ , thiogallates and thioaluminates activated with at least one of Ce 3+  and Eu 2+ , oxysulfides activated with at least Eu 3+ , complex fluorides activated with Mn 4+ , and any combination thereof. 
     
     
         3 . The lighting device of  claim 1 , wherein the phosphor is selected from alkaline earth thiogallates activated with at least Eu 2+ , rare earth oxysulfides activated with at least Eu 3+ , alkali fluorides activated with Mn 4+ , and any combination thereof. 
     
     
         4 . The lighting device of  claim 2 , wherein the complex fluoride activated with Mn 4+  is selected from (1) A 2 [MF 6 ]:Mn 4+ , wherein A is selected from Li, Na, Rb, Cs, NH 4 , and combinations thereof; and M is selected from Ge, Si, Sn, Ti, Zr, Hf and combinations thereof; (2) A 3 [MF 6 ]:Mn 4+ , wherein A is selected from Li, Na, Rb, Cs, NH 4 , and combinations thereof; and M is selected from Al, Ga, In Bi, Sc, Y, a rare earth; and any combination thereof. 
     
     
         5 . The lighting device of  claim 2 , wherein the complex fluoride activated with Mn 4+  is selected from K 2 [TiF 6 ]:Mn 4+ , (K,Cs)[SiF 6 ]:Mn 4+ , and any combination thereof. 
     
     
         6 . The lighting device of  claim 1 , wherein the phosphor comprises SrGa 2 S 4 :Eu 2+ . 
     
     
         7 . The lighting device of  claim 1 , wherein the phosphor optionally comprises an additional phosphor that is selected from the group including: (Ba,Sr,Ca) 5 (PO 4 ) 3 (Cl,F,Br,OH):Eu 2+ ,Mn 2+ ; (Ba,Sr,Ca)BPO 5 :Eu 2+ ,Mn 2+ ; (Sr,Ca) 10 (PO 4 ) 6 *vB 2 O 3 :Eu 2+  (wherein 0<v≦1); Sr 2 Si 3 O 8 *2SrCl 2 :Eu 2+ ; (Ca,Sr, Ba) 3 MgSi 2 O 8 :Eu 2+ , Mn 2+ ; BaAl 8 O 13 :Eu 2+ ; 2SrO*0.84P 2 O 5 *0.16B 2 O 3 :Eu 2+ ; (Ba,Sr,Ca)MgAl 10 O 17 :Eu 2+ , Mn 2+ ; (Ba,Sr,Ca)Al 2 O 4 :Eu 2+ ; (Y,Gd,Lu,Sc,La)BO 3 :Ce 3+ ,Tb 3+ ; ZnS:Cu 3+ ,Cl − ; ZnS:Cu + ,Al 3+ ; ZnS:Ag + ,Cl − ; ZnS:Ag + ,Al 3+ ; (Ba,Sr,Ca) 2 Si 1-ξ O 4-2ξ :Eu 2+  (wherein 0≦ξ≦0.2); (Ba,Sr,Ca) 2 (Mg,Zn)Si 2 O 7 :Eu 2+ ; (Sr,Ca,Ba)(Al,Ga,In) 2 S 4 :Eu 2+ ; (Y,Gd,Tb,La,Sm,Pr,Lu) 3 (Al,Ga) 5-α O 12-3/2α :Ce 3+  (wherein 0≦α≦0.5); (Ca,Sr) 8 (Mg,Zn)(SiO 4 ) 4 Cl 2 :Eu 2+ , Mn 2+ ; Na 2 Gd 2 B 2 O 7 :Ce 3+ ,Tb 3+ ; (Sr,Ca,Ba,Mg,Zn) 2 P 2 O 7 :Eu 2+ ,Mn 2+ ; (Gd,Y,Lu,La) 2 O 3 :Eu 3+ , Bi 3+ ; (Gd,Y,Lu,La) 2 O 2 (S,Se,Te):Eu 3+ , Bi 3+ ; (Gd,Y,Lu,La)VO 4 :Eu 3+ ,Bi 3+ ; (Ba,Sr,Ca)MgP 2 O 7 :Eu 2+ , Mn 2+ ; (Y, Lu) 2 WO 6 :Eu 3+ ,Mo 6+ ; (Ba,Sr,Ca) β Si γ N μ :Eu 2+  (wherein 2β+4γ=3μ); Ca 3 (SiO 4 )Cl 2 :Eu 2+ ; (Lu,Sc,Y,Tb) 2−u−v Ce v Ca 1+u Li w Mg 2-w P w (Si,Ge) 3-w O 12-u/2  (where −0.5≦u≦1, 0<v≦0.1, and 0≦w≦0.2); ((Y,Lu,Gd) 2-φ Ca φ Si 4 N 6+φ C 1−φ :Ce 3+ , (wherein 0≦φ≦0.5); (Lu,Ca,Li,Mg,Y)alpha-SiAlON doped with Eu 2+  and/or Ce 3+ ; (Ca,Sr,Ba)SiO 2 N 2 :Eu 2+ ,Ce 3+ ; 3.5MgO*0.5MgF 2 *GeO 2 :Mn 4+ ; Ca 1−c−f Ce c Eu f Al 1+c Si 1−c N 3 , (where 0<c≦0.2, 0≦f≦0.2); Ca 1−h−r Ce h Eu r Al 1−h (Mg,Zn) h SiN 3 , (where 0<h÷0.2, 0≦r≦0.2); Ca 1−2s−t Ce s (Li,Na) s Eu t AlSiN 3 , where 0≦s≦0.2, 0≦f≦0.2, s+t>0); Ca 1−σ−χ−φ Ce σ (Li,Na) χ Eu φ Al 1+σ−χ Si 1−σ+χ N 3 , (where 0≦σ≦0.2, 0<χ≦0.4, 0≦φ≦0.2), and any combination thereof. 
     
     
         8 . The lighting device of  claim 1 , wherein the opposed at least substantially transparent members are plates, and a perimeter seal envelopes edges of said plates. 
     
     
         9 . The lighting device of  claim 8 , wherein said perimeter seal comprises an adhesive tape that comprises at least one layer of air- and moisture-impermeable material. 
     
     
         10 . The lighting device of  claim 8 , wherein the plates are made of glass. 
     
     
         11 . The lighting device of  claim 8 , wherein the perimeter seal comprises UV curable acrylic or epoxy. 
     
     
         12 . The lighting device of  claim 1 , further including a RI matching layer between the plates. 
     
     
         13 . The lighting device of  claim 1 , wherein the radiation source comprises one or more a light emitting diodes (LED). 
     
     
         14 . The lighting device of  claim 1 , further including a light diffuser placed between the radiation source(s) and the phosphor layer. 
     
     
         15 . A display device comprising one or more radiation sources and a layer of secured phosphor, wherein said layer of phosphor is located between opposed at least substantially transparent members comprised of a material substantially impervious to an external atmosphere. 
     
     
         16 . The display device of  claim 15 , which is a LCD display including a polarizer, an array of thin film transistors (TFT) and color filter. 
     
     
         17 . The display device of  claim 16 , further including a brightness enhancement filter or brightness enhancing film (“BEF”), a UV filter, a mask, or a combination thereof. 
     
     
         18 . A backlighting device, which comprises one or more radiation sources and a layer of moisture sensitive phosphor, wherein said layer of phosphor is located between opposed at least substantially transparent members comprised of a material substantially impervious to an external atmosphere. 
     
     
         19 . The backlighting device of  claim 18 , wherein the phosphor is selected from sulfides, selenides, tellurides, activated with at least one of Ce 3+  and Eu 2+ , thiogallates and thioaluminates activated with at least one of Ce 3+  and Eu 2+ , oxysulfides activated with at least Eu 3+ , complex fluorides activated with Mn 4+ , and any combination thereof. 
     
     
         20 . The backlighting device of  claim 18 , wherein the phosphor is selected from alkaline earth thiogallates activated with at least Eu 2+ , rare earth oxysulfides activated with at least Eu 3+ , alkali fluorides activated with Mn 4+ , and any combination thereof.